1. Field of the Invention
The present invention relates to an information recording and reproducing device that can record and reproduce information onto or from an optical disk such as a DVD (Digital Versatile Disk).
2. Description of the Background Art
For recording data onto a DVD+RW disk that is a kind of recordable DVD disk, formatting processing is required before data recording.
In response to a formatting request of a user, the DVD+RW disk is processed such that a notification of completion of the formatting is provided to the user when only a part of a lead-in region is recorded, and then so-called background formatting will be performed. Thus, dummy data will be recorded on a residual region while access according to a user's access request is not performed.
This background formatting significantly reduces a formatting time that is long in a prior art.
In the background formatting, a device continuously records dummy data on a data region starting from its inner periphery.
When the device receives a data record request from a user during the background formatting, it interrupts the background formatting, and performs the requested data recording after updating an LWA (Last Written Address) of the continuous record.
After the data recording is completed, the formatting processing restarts from the LWA. During the background formatting, the user can perform random recording of data on the whole data region.
Thus, the formatting processing allows recording of the data even on a region on which the dummy data is not yet recorded by the formatting processing, and therefore data recorded regions and data unrecorded regions are present in a mixed fashion if the user performs the data recording during the background formatting. For resuming the background formatting when the data recorded regions and the data unrecorded regions are present in a mixed fashion, the dummy data must be recorded on the regions other that the regions where the user has already recorded the data. Therefore, the information recording and reproducing device generally employs such a managing manner that a record state, e.g., of a region (1 ECC block=16 sectors in the case of the DVD+RW disk) forming a record unit is managed with a flag (bit map information) of one bit.
More specifically, when the user performs the data recording on a region radially outside the LWA, the flag on the bit map corresponding to this region is set to “recorded”. For resuming the background formatting thereafter, the dummy data recording is performed on only the unrecorded region with reference to this bit map information.
When the DVD+RW disk is used, the background formatting can be interrupted for taking out the disk.
In this case, the LWA and bit map information are recorded in an FDCB (Formatting Disk Control Block) in the lead-in region.
When the disk that was partially formatted is reloaded, the FDCB can be referred to, and thereby the background formatting can be resumed to record dummy data only in the unrecorded region.
When the background formatting is interrupted and the disk is taken out, the FDCB serves as very important information for determining the record state of the disk. When a failure occurs in updating of the FDCB, such a problem may occur that the background formatting will overwrite the data recorded by the user with the dummy data.
As an example of use of the DVD+RW disk, there is real-time recording of, e.g., TV programs. For such real-time data recording, a user requests the data recording with a relatively low transfer rate and constant intervals. For performing the real-time data recording during the background formatting, therefore, the dummy data recording for the formatting processing is not performed, the data recording requested by the user continues until the record time elapses. In other words, the record updating of the FDCB cannot be performed during the real-time data recording, and this may result in a problem that the FDCB cannot be accurately updated, e.g., when unexpected power interruption occurs during recording due to a power failure or the like.
When the above disk is reloaded, erroneous information is recorded in the LWA and/or the bit map information to be referred to for resuming the background formatting. This results in a problem that the formatting overwrites the user data already recorded with the dummy data.
Japanese Patent Laying-Open No. 2005-038570 has disclosed a manner in which user data recording on a disk is interrupted during execution of the data recording based on whether a quantity of data stored in a cache memory exceeds a predetermined threshold or not, and a FDCB is updated during the interruption.
According to the manner disclosed in the above reference, however, the data recording must be interrupted whenever the data quantity exceeds the predetermined threshold, and this lowers the performance of data recording. Since the FDCB of the disk is updated whenever the quantity exceeds the predetermined threshold, this increases the number of times of updating the FDCB. Since the number of times of the FDCB updating cannot be increased infinitely, such updating may degrade the disk.